Spindle cell carcinoma of the lip: An immunohistochemical study of a challenging case.

INTRODUCTION:Spindle cell carcinoma (SpCC) or sarcomatoid carcinoma, is a rare variant of squamous cell carcinoma (SCC) that has a variable proportion of carcinomatous and sarcomatous components. Here, we reported an immunohistochemical study of a spindle cell carcinoma with a challenging morphological diagnosis. CASE REPORT:A 50-year-old woman with a previous history of nodular melanoma was referred for evaluation of a painful papule in the lower lip. After surgical resection, neoplastic cells showed focal positivity for CK-14, αSMA, p63, and confirmed the strong positivity for S100 and vimentin. Tumor cells were negative for HMB-45, Melan A, SOX-10, AE1/AE3, 34βE12, CK5-6, CAM5.2, EMA, desmin, calponin, CD10, CD34, and CD68. With these findings, a diagnosis of SpCC was rendered. The patient presented lung and dorsal metastases after 12 months and after 3 years of follow-up, the patient died. CONCLUSION:In summary, a careful correlation of microscopy and immunohistochemical characteristics is required for the proper diagnosis of this lesion.